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fxus63 kmpx 201133 

Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
633 am CDT Fri Jul 20 2018

issued at 624 am CDT Fri Jul 20 2018

Updated to include 12z aviation discussion below.


Short term...(today and tonight)
issued at 245 am CDT Fri Jul 20 2018

Surface analysis and infrared satellite imagery early this morning shows
a rotating surface low slowly migrating east over southern Minnesota
into southwestern WI. A secondary surface cold front emanating
from another surface low over southwestern Ontario province
extends southwest through northwestern Minnesota into central South Dakota. Aloft,
a 500 mb low is nearly atop the surface feature within a shortwave
trough, with a ridge axis building north from The Four Corners
region through the northern plains.

The western ridge axis will slowly shift east today which will
help nudge the deep low eastward, but not before additional
showers drift south-southeast through mainly eastern Minnesota into
western WI, in response to daytime heating sparking the showers.
Not looking for anything strong but the hit-and-miss brief showers
will be a nuisance across the area through the late afternoon
hours. Also not looking for much in the way of thunderstorms, and
even less so strong/severe ones, but with MUCAPE still progged to
reach the 500- 1000 j/kg range in eastern Minnesota into western WI,
isolated thunderstorms cannot be ruled out. The activity will wane
with the loss of heating this evening then shift off to the east
overnight into Saturday morning, resulting in partial clearing by

Compared to yesterday, temperatures will run a little warmer in
western-central Minnesota due to the partial clearing expected while
running the same or a little cooler in far eastern Minnesota into western
WI with the continued cloud/rain complications. Overall, highs will
still range through the 70s today. Lows tonight will again run in
the upper 50s to mid 60s.

Long term...(saturday through thursday)
issued at 245 am CDT Fri Jul 20 2018

The longer term concerns remain timing of cold frontal passages
and overall temperature trend.

The closed circulation over the Great Lakes will move slowly east
over the weekend. Some small risk of showers developing mainly
over west central WI region Saturday, depending on how much
moisture remains. Confidence remains low and feel overall coverage
will be very limited so wont include at this time. Clouds will
remain, especially to the east Saturday and this will likely hold
temepratures in the 75 to 80 degree range over the area.

This below normal temperature trend will likely continue Sunday
as well, but sunshine should be more prevalent. Timing of the next
front appears to be the Monday/Monday night time frame, with the
European model (ecmwf) a little slower than the GFS. We will continue to hold onto
small chance pops for this frontal passage. Instability is weak as
well so thunder should be limited.

Timing of the midweek front appears to be Tuesday night through
Wednesday. The GFS is a bit stronger with the upper trough and
does generate some MUCAPE to 1500 j/kg with this feature into
Wednesday. This should be the better chance for thunder during the
week. We trend cooler as this front moves through. Temperatures
should remain below normal through the remainder of the week.


Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 624 am CDT Fri Jul 20 2018

Low clouds with spotty -dz/-ra to start the period and likely
continue through at least late morning. As the afternoon
progresses, there is a growing chance of isolated/scattered -tsra
in mainly eastern Minnesota into western WI. At worst, MVFR conditions
are expected but this may change should thunderstorm coverage be
more than expected at this point. Precipitation looks to end by
early evening then be followed by VFR into the early morning
hours. MVFR, and possible IFR, ceilings are then likely to develop
during the pre-dawn hours on Saturday.

Kmsp...ceilings will bounce between IFR and MVFR for the first
couple hours of the 20/12z taf then settle into MVFR for much of
the day. Similarly, spotty showers will come and go over near and
over msp, with isolated thunderstorms possible this afternoon.
Precipitation looks to end this evening, coinciding with VFR
ceilings, followed by MVFR ceilings overnight through daybreak

/Outlook for kmsp/
Sat...VFR. Wind north 10 kts.
Sun...VFR. Wind NE 5 kts.
Mon...VFR. Wind vrbl becoming northwest 5 kts.


Mpx watches/warnings/advisories...


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